How to grow leek
Allium ampeloprasum · Amaryllidaceae · Vegetable
When to plant leeks: the short answer
Start seeds indoors about 10 weeks before your last spring frost; plant out about 2 weeks before it; sow outdoors about 2 weeks before the last frost. Seeds germinate in soil from 45 to 80°F, fastest near 70°F.
Zone 5: plant out Apr 9 – Apr 26. Zone 7: plant out Mar 15 – Apr 1. Zone 9: plant out Jan 30 – Feb 16. See every zone.
Leek is a cool-season vegetable in the Amaryllidaceae family, usually started indoors and set out as transplants. It wants full sun (six or more hours of direct light) and steady, even moisture. From sowing to first pick is about 100–150 days. It is one of the toughest crops here, standing through hard frost and often improving for it.
Grower’s note: Long season - start early indoors. Drop seedlings into a 6 in dibbed hole and water in rather than backfilling; hill soil up the stems through summer to blanch the white shank. Stands in the ground through hard frost.
Sowing
Sow about 0.5″ deep, into soil between 45–80°F — germination is quickest near 70°F. Germination takes a week or two (7–14 days). For an early crop, start seed indoors about 10 weeks before your last spring frost and grow it under bright light.
Spacing & layout
Give each plant about 6″ along the row with roughly 12″ between rows. On a square-foot grid that is 9 per square foot. Allow at least 12″ of loose, workable soil for the roots. It grows well in containers at least 12″ deep.
Fitting it to your season
As a cool-season crop, leek does its best growing in the mild weather of spring and fall and tends to bolt or turn bitter in summer heat.
Quick facts
Growth stages: how long leeks take to grow
From seed to first harvest takes roughly 22-29 weeks: about 8 weeks as a seedling indoors, then 100-150 days in the garden.
When to plant leek
When to plant leeks by USDA zone
Dates worked out from each zone’s typical frost dates for 2026. Find your zone on the zone map, or pick your state below for dates from its own frost dates. Zones 11 and above are frost-free, so timing there depends on heat and rain instead.
| Zone | Last / first frost | Start indoors | Sow or plant out |
|---|---|---|---|
| Zone 3 | May 15 / Sep 15 | Feb 27 – Mar 13 | Apr 24 – May 11 |
| Zone 4 | May 10 / Sep 25 | Feb 22 – Mar 8 | Apr 19 – May 6 |
| Zone 5 | Apr 30 / Oct 5 | Feb 12 – Feb 26 | Apr 9 – Apr 26 |
| Zone 6 | Apr 15 / Oct 15 | Jan 28 – Feb 11 | Mar 25 – Apr 11 |
| Zone 7 | Apr 5 / Oct 25 | Jan 18 – Feb 1 | Mar 15 – Apr 1 |
| Zone 8 | Mar 20 / Nov 5 | Jan 2 – Jan 16 | Feb 27 – Mar 16 |
| Zone 9 | Feb 20 / Nov 30 | Dec 5 – Dec 19 | Jan 30 – Feb 16 |
| Zone 10 | Jan 30 / Dec 15 | Nov 14 – Nov 28 | Jan 9 – Jan 26 |
Companions
Carrot, Celery, Onion, Cabbage
Bush Bean, Pole Bean, Pea
Common problems
Pests: onion maggot, onion thrips, leek moth.
Diseases & disorders: rust, white rot.
Same family (Amaryllidaceae)
Rotate these so they don’t follow each other in the same bed year to year.
Questions gardeners ask
When should I plant leeks?
Start seeds indoors about 10 weeks before your last spring frost; plant out about 2 weeks before it; sow outdoors about 2 weeks before the last frost. Seeds germinate in soil from 45 to 80°F. The table on this page gives dates for each USDA zone, and the planting calendar gives dates for your own state or ZIP code.
How long do leeks take to grow?
About 100-150 days from transplanting to the first harvest, or roughly 22-29 weeks from sowing the seed indoors. Seeds germinate in 7-14 days.
How much sun do leeks need?
They need at least six to eight hours of direct sun a day.
What soil pH do leeks need?
A soil pH between 6.0 and 8.0. It tolerates neutral to slightly alkaline soil better than most vegetables. Test before adding lime or sulfur - see the soil pH and testing guide.
How far apart should I plant leeks?
Space plants about 6 inches apart in rows 12 inches apart, or 9 per square foot in a square-foot bed. Sow seeds about ½ inch deep.
Can I grow leeks in a container?
Yes. Use a container at least 12 inches deep with drainage holes and a good potting mix, and water more often than you would in the ground.
Figures are typical home-garden ranges from Cooperative Extension planting guides, cross-checked against multiple state sources. Your variety and conditions will vary.